From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Wed, 8 Jul 2015 20:46:52 -0400
Subject: Initial commit

---
 pkg/plot/doc/pvector.hlp | 191 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 191 insertions(+)
 create mode 100644 pkg/plot/doc/pvector.hlp

(limited to 'pkg/plot/doc/pvector.hlp')

diff --git a/pkg/plot/doc/pvector.hlp b/pkg/plot/doc/pvector.hlp
new file mode 100644
index 00000000..34ab1590
--- /dev/null
+++ b/pkg/plot/doc/pvector.hlp
@@ -0,0 +1,191 @@
+.help pvector Oct91 plot
+.ih
+NAME
+pvector -- plot an arbitrary vector in a 2D image
+.ih
+USAGE
+pvector image x1 y1 x2 y2
+.ih
+PARAMETERS
+.ls image
+Input image containing data to be plotted.
+.le
+.ls x1, y1
+Starting coordinates of the vector to be plotted.
+.le
+.ls x2, y2
+Ending coordinates of the vector to be plotted.
+.le
+.ls xc, yc
+The center coordinates of the vector to be plotted if the position
+angle \fItheta\fR is defined.
+.le
+.ls width = 1
+Number of pixels perpendicular to the vector to average.
+.le
+.ls theta = INDEF
+The postion angle of the vector to be plotted measured counter-clockwise
+from the positive x axis. Theta must be between 0.0 and 360.0 degrees.
+If theta is specified, the \fIxc\fR, and \fIyc\fR parameters
+must be specified instead of the starting and ending coordinates
+as in examples 3 and 4.
+.le
+.ls length = INDEF
+The length of the vector to be plotted if \fItheta\fR is defined. The
+default is to plot the vector from one edge of the frame to another.
+.le
+.ls boundary = constant
+The type of boundary extension. The boundary extension options are:
+.ls nearest
+Use the value of the nearest boundary pixel.
+.le
+.ls constant
+Use a constant value.
+.le
+.ls reflect
+Generate a value by reflecting around the boundary.
+.le
+.ls wrap
+Generate a value by wrapping around to the opposite side of the image.
+.le
+.le
+.ls constant = 0.
+The constant for constant valued boundary extension.
+.le
+.ls vec_output = ""
+File or image name if output vector is desired.  If this parameter is
+non-null, then the computed vector will be output to the named file of
+the type specified by the \fIout_type\fR parameter.  If set to STDOUT
+or STDERR, a listing of the pixels (i.e. text format) will be output to 
+either of these streams.  Plotting is disabled if vector output is selected.
+.le
+.ls out_type = "text"
+Type of output format (image|text). If an image is created, then a new
+header keyword, "VSLICE", will be appended to the new image describing
+the endpoints of the vector, the width, and the parent image name. The 
+parent image header will be copied to the new image.
+.le
+.ls wx1 = 0., wx2 = 0., wy1 = 0., wy2 = 0.
+The range of world coordinates to be included in the plot.  If the
+range of values in x or y is zero, the plot is automatically scaled from the
+minimum to maximum data values along the degenerate axis.
+.le
+.ls vx1 = 0., vx2 = 0., vy1 = 0., vy2 = 0.
+NDC coordinates (0-1) of the device plotting window.  If not set by user,
+a suitable viewport which allows sufficient room for all labels is used.
+.le
+.ls pointmode = no
+Plot individual points instead of a continuous line?
+.le
+.ls marker = "box"
+Marker or line type to be drawn.  If \fBpointmode\fR = yes the markers are
+"point", "box", "cross", "plus", "circle", "hebar", "vebar", "hline",
+"vline" or "diamond".  Any other value defaults to "box".  If drawing lines,
+\fBpointmode\fR = no, the values are "line", "lhist", "bhist".  Any other
+value defaults to "line".  "bhist" (box histogram) draws lines to the
+bottom of the graph while "lhist" does not.  In both cases the
+horizontal histogram lines run between the half way points (reflected
+at the ends).
+.le
+.ls szmarker = 0.005
+The size of the marker drawn when \fBpointmode\fR = yes.
+.le
+.ls logx = no, logy = no
+Draw the x or y axis in log units, versus linear?
+.le
+.ls xlabel = "", ylabel = ""
+The x-axis and y-axis labels.
+.le
+.ls title = "imtitle"
+Title for plot.  If not changed from the default, the title string from the
+image header, appended with the vector endpoints, is used.
+.le
+.ls majrx = 5, minrx = 5, majry = 5, minry = 5
+The number of major and minor divisions along the x or y axis.
+.le
+.ls round = no
+Round axes up to nice values?
+.le
+.ls fill = yes
+Fill the output viewport regardless of the device aspect ratio?
+.le
+.ls append = no
+Append to an existing plot?
+.le
+.ls device = "stdgraph"
+Output device.
+.le
+.ih
+DESCRIPTION
+Plot an arbitrary vector of data from an image.  The vector can be
+specified by either defining the two endpoints of the vector or 
+by specifying the center position, length and position angle of the vector.
+The user can specify
+the plot size and placement, the scaling and labeling of axes.  Data can be
+plotted as a continuous line or individual points with a specified marker.
+Optionally, the computed vector may be output to a named image or text file
+(as specified by the \fIvec_output\fR and \fIout_type\fR parameters).
+
+The vector is extracted as a straight line between the given
+coordinates, sampled at a spacing along that line equivalent to that
+between adjacent pixels in the x or y direction (e.g. the length of a
+diagonal endpoint vector from a square image is n*sqrt(2)).
+It is possible to specify an averaging width
+which determines how many pixels perpendicular to the vector are averaged.
+This averaging window is centered
+on the vector pixel.  When this window is greater than one pixel, it
+is possible that the extraction process might try to exceed the
+image boundary, in which case the specified type of boundary extension
+is employed. The extraction algorithm uses bilinear interpolation to
+evaluate points at non-integral pixel positions.
+
+If \fBappend\fR is enabled, previous values for \fBbox\fR,
+\fBfill\fR, \fBround\fR, the plotting viewport (\fBvx1\fR, \fBvx2\fR, 
+\fBvy1\fR, \fBvy2\fR), and the plotting window (\fBwx1\fR, \fBwx2\fR, 
+\fBwy1\fR, \fBwy2\fR) are used.
+
+If the plotting viewport was not set by the user, \fBpvector\fR 
+automatically sets a viewport centered on the device.  The default value
+of \fBfill\fR = yes means the plot spans equal amounts of NDC space in
+x and y.  Setting
+the value of \fBfill\fR  to "no" means the viewport will be adjusted so 
+that the square plot will span equal physical lengths in x and y
+when plotted.  That is, when \fBfill = no\fR, a unity aspect ratio is 
+enforced, and plots
+appear square regardless of the device aspect ratio.  On devices with non 
+square full device viewports (e.g., the vt640), a plot drawn by \fIpvector\fR
+appears extended in the x direction unless \fBfill\fR = no.
+
+.ih
+EXAMPLES
+1. Plot from the lower left to upper right of 512 square image crab.5009.
+
+    cl> pvector crab.5009 1. 1. 512. 512.
+
+2. Plot the same vector but with the sampling width = 3.
+
+    cl> pvector crab.5009 1. 1. 512. 512. width=3
+
+3. Plot a vector in same image with center position 256, 256, and a position
+angle of 45 degrees which extends from one edge of the frame to the other.
+
+    cl> pvector crab.5009 0. 0. 0. 0. 256. 256. theta=45.
+			or
+    cl> pvector crab.5009 xc=256. xc=256. theta=45.
+
+
+4. Plot the above vector with a length of 100 pixels.
+
+    cl> pvector crab.5009 0. 0. 0. 0. 256. 256. theta=45. length=100.
+			or
+    cl> pvector crab.5009 xc=256. xc=256. theta=45. length=100.
+.ih
+TIME REQUIREMENTS
+It takes approximately 6.7 cpu seconds to compute and plot the twenty
+pixel wide diagonal of a 512 square real image. (VAX/VMS 750 with fpa).
+.ih
+BUGS
+.ih
+SEE ALSO
+prow, pcol, prow, pcols
+.endhelp
-- 
cgit 

